86 freightliner flc120 running lights random turn off help

Hello.
My run lights on my 1986 freightliner flc120 just randomly cut off. I leave toggle switch off for a while and then they’ll the back on.
This has been happening for a year before I just put new top of cab lights and side marker lights below doors. Still does it.
I pull all relays and no relay seems to control it?
I wire up lots of 12v stuff all my life but this is odd.
This even happens with trailer wire 7-way unhooked.
It’s as if something heats up and cuts it off.
I look at wiring diagram on back of dash panel and maybe a relay “should” be controlling it but it’s not? Haven’t been able to trace wire yet.
Any tips?

On a side note...where can I get quality relays for my truck? And the little (two stud box relay looking things (additional mini relay?) behind nut driver size wire connector strip? What are those things called?

The big relays are aluminum box type that say:
Bosch Germany

0332204101

12v 20/30A

Are newer plastic ones that match up in specs pretty good? What specs do I need? I want to keep extras in truck for emergency.

 

Thanks. I was about to say I think they are circuit breakers but wasn’t sure if exact term at moment. What makes me wonder is why there are no fuses? Must be a good reason?
So, maybe my running lights are wired into just a circuit breaker and the breaker is failing? How to test? Hmmm. Just replace? Napa?

Thanks!

 

Thanks for the tip. So I removed the circuit breaker that the wiring diagram shows. #46 wire from 5 (top of cab) marker lights. Of course, the 4 side truck market lights (2 below each door) aren’t shown in diagram. My 2 per side lights seem to have a wire that comes up through back of floorboard on each side of cab corners and thread under carpet Center bottom dash wiring central.

What is odd is that the circuit breaker (2nd row left from top as seen in one attached pic {brass flat strip hub}) (inside the bottom of the v shape of blue wire) for circuit breakers) has a flat jumper brass connector that crosses over to right hand side behind nuts.

Maybe I need to replace both sides?
I wonder if these circuit breakers control the trailer clearance lights as well. I think #23 (as seen in wiring diagram in attached pic) is the wire that runs to trailer tail lamp relay.

I guess I should go by a napa and match up the circuit breaker. Or amazon.

The circuit breaker on left side 2 from top is:
short stop type 2 12v 10 amp circuit breaker

And I assume the right strip side 2 from top is same but 30 amp relay.